teacher, you're exposed to a lot of things. >> reporter: now with the flu spreading, clinics nationwide are reporting spot shortages of the vaccine. in new york, karen goodson finally got her flu shot. >> thank you. >> reporter: after the first clinic she visited ran out of the vaccine twice in one day. >> we had been waiting there for 20 minutes, they said, oh, no more flu shots, sorry, we have to go home. >> reporter: everyone older than six months get the flu shot, but during the last two flu seasons, fewer than half actually receive the vaccine. last year, south dakota had the highest vaccination rate, 51% of the state, while nevada had the lowest vaccination rate last year at just 32%. in montgomery county, maryland, just outside of d.c., fire department ambulances are often rerouted to different e.r.s since so many hospitals are already full with flu patients, especially the elderly.